Blizzard has indeed used "storage choices" as a reason for limited stash and inventory space.
For which they should be slapped tbh.
I'm all for meaningful choices, but it kinda has to be fun too.
Playing Storage Tetris or having to destroy items to keep others is just really stupid design. It adds nothing to the game tbh.
It cant be compared to 6 skill slot limiting, which adds challenge and the choice of strengths/weaknesses to a game (well, it would have if you could not free-spec).
If you want to give players meaningful choices for getting rid of items, then you do it through stuff like salvaging.
If a perfectly rolled legendary salvaged into better materials than a crappy legendary, then I would have a meaningful choice on keeping the legendary or salvaging it.
I didn't say I disagreed with you, I said I thought that was what the devs intended. That said, I also don't necessarily agree with you either. I agree that playing Storage Tetris is annoying and doesn't add anything to the game, but I don't necessarily think that the system is set up to encourage Storage Tetris. It depends on the drop rates of legs/sets and the usefulness of Enchanting legs/sets. If it is very useful to Enchant legs/sets, then item storage shouldn't be a problem. Assuming a mostly clear stash (since lvl 60 gear will be mostly useless at RoS lvl 70), you have 70 slots per page, for 210 slots total. Assuming you have a few gems of each kind (Marquise and up), let's assume that you have 50 open slots on the first page and all 70 open on the next two (190 total). Since each item, barring rings and amulets, takes up 2 spaces, you will probably have a bit more than 100 slots for gear. Between six classes, this is pretty low, especially given the numerous itemization changes that make alternate gear sets far more useful, due to elemental damage differences and different preferences for CDR and RCR. Dividing the 100 slots by six classes gets you approximately 16/17 slots per class. Just to clarify, by slots, I mean 'places to put a piece of gear;' the in-game number of slots should be double what I'm listing, since I'm listing by 'number of places you can put a 2-slot gear piece in.' If instead you want to place gear only by mainstat instead of class, then you have roughly 33/34 slots per stat.
At the moment, I feel that this amount is too little. It would probably be alright if the itemization wasn't improving, because right now, gear requirements are pretty homogenous, and different gear sets aren't worth too much. Since the itemization has improved, and new builds are being enabled, the stash size should increase. I feel, as I stated in the post above this one, that doubling the amount of space would accomplish this goal nicely. If you had 32/33 'slots' per class, then you could gear up about 2-and-a-half full item sets (full set is 13 items, of which 4 take up 1 slot and 9 take up 2 slots). Since you would be wearing a full set of gear, this would amount to being able to have 3-and-a-half full sets of gear per character class in the stash.
Considering that the above scenario takes place in a universe where Enchanting is useful, and you want to break down legs/sets in order to Enchant your current gear, this should be more than enough room for all classes. The extra room that would be taken up by other legs/sets would be freed up, since you'd be salvaging a lot of non-optimal legs/sets in order to perfect your current gear, or an alt-set. As an endgame goal, this should be fine, and I'll explain why. In the current opinion of the devs, legs/sets should be the endgame item hunt, and an optimized player should, eventually, only be wearing legs/sets. Since it takes forgotten souls to Enchant legs/sets, this means that you need at least 13 souls to Enchant each item once. However, since from what I've heard of RoS Enchanting seldom goes as you want it to the first time, you may have to Enchant more than once. On an average of 3 Enchants until you get what you want, this means that you'd need 39 souls to fully enchant a single gear set, and therefore, that you'd need to break down 39 legs/sets in order to have a perfect item set. Given this example, if each class gets to store 3-and-a-half item sets overall, then it would take about 137 legs/sets per class in order to completely perfect the gear on your character and in your stash. For reference, that's 822 legs/sets overall. Most people have never even found 822 legs/sets overall! I believe that for this scenario at least, the amount of stash space should be fine. You'll decide what you want to play, keep the legs/sets that help you play that way, and break down any that don't in order to buff your current ones (or, when your current ones are perfect, to start buffing the next set so your next style can be optimized).
This is, of course, assuming that Enchantment is a useful and viable method of improving items. If Enchanting is as useful as current crafting in terms of getting upgrades (read: not very), then the situation changes rather considerably, and most people will not break down legs/sets to buff items, since there will be a feeling of uselessness to the ordeal, much like buying a Lotto ticket at the supermarket. Some people will still do it, but the dynamic will be off. As a result, if Enchanting goes well, or if forgotten souls become useful for more than just creating crafted legs/sets and Enchanting stuff, then IMO simply doubling the number of tabs would suffice to solve the problem. On the other hand, if it doesn't, then Blizzard will have to either very quickly fix the problem, or provide more stash pages. The alternative, which sadly is looking more and more likely, is that Blizzard will do nothing, regardless of Enchanting's success or failure. As I said, I agree that it is a problem. It remains to be seen whether or not the problem will be answered. RoS is doing a lot to make the game better and shore up faults, but in the end, the devs have said nothing about increasing stash size, and so it seems likely that unless a major complaint is made, similar to the complaints about items, the devs will do nothing.
As a side idea, Blizzard could always just sell extra stash tabs as a microtransaction. As far as I know, GGG from PoE does something similar; I know it sells stash tabs for guilds, and I believe it also sells tabs for single players. Blizzard could probaby just do that. I'm sure it would piss off some number of players, but as long as the amount of money per tab was not too high (maybe USD $2-3, or Euro $1-2) then it shouldn't be a real problem. It also enables more pack-rat-ish players to maintain a bigger stash, rather than confining everyone to the same limit. Just an idea.
EDIT: You sly dog, Ivan E, you beat me to it!